Means for conditioning sugar bearing materials



Sept 2, 1941- c. A. oLco'rT 2,254,387

MEANS FOR CONDITIONING SUGAR BEARING MATERIALS I ATTORNEY Sept 2 1941-v c. A. oLcoT-r 2,254,387

MEANS FOR CONDITIONING SUGAR BEARING MATERIALS Filed March l1, 19259y 2 Sheets-Sheet 2 FIG. 4

A 7 TORNE Y Patented Sept. 2, 1941 A UNITED STATES PATENT OFFICE 'www Y I I MEANS FOR COGNDMIIONINGSSUGAB Charles A. Olcott, West Milford, N. J. Application March 11, 1939, Serial No. 261,185 s claims. (ci. 121-19) This invention relates to the processing' of sugar bearing materials and more particularly to methods and means of conditioning such materials to extract sugar therefrom.

An object of this invention is to obtain the maximum yield of sugar from sugar bearing material.

Another object of this invention is to improve the purity of sugar obtained from sugar bearing material.

Another object of this vinvention is in the extraction of sugar from sugar bearing material to prevent caramelization or destruction of sugar.

A more particular object of this invention is to attain the optimum temperature range requisite for efficient processing of sugar in a sugar bearing material without destruction or damaging of the sugar due to local overheating.

In vthe extraction of sugar from sugar magmaV or like materials, the process of cooling the magma to cause crystallization of a large proportion of the sugar content is followed by heating of the magma, withv the sugar crystals dispersed throughout it, to increase its uidity so that it will be well adapted for the next step, viz., centrifugal separation of the crystals. 'I'he characteristics of the magma and of the sugar crystals are such that the temperature of the mass must be maintained within a narrow temperature range throughout the heating process. Too low a temperature and the magma becomes so viscous that centrifuging is practically impossible; too high a temperature and the sugar crystals begin to re-dissolve in the mother liquor, i. e., the magma, or carameliration of the sugar may even occur, in either of which events the yield of sugar of commercial quality may be substantially reduced. 1

The usual hot mingler for effecting the heating step described comprises a tank through which the sugar-bearing magma is passed and in which are rotating coils that carry hot water or other heating fluid. In one type of hot mingler used commercially the temperature of the heating fluid is only slightly above the temperature to which it is desired that the magma shall be heated, and not hig enough to cause substantial re-dissolution of the sugar crystals or other deleterious effect. In a second commercial type of hot mingler, the temperature of the heating fluid is far in excess of any temperature to which the magma itself could safely be raised. Rotation of the coils, however, tends even distribution of the heat delivered by them, and their speed of movement through the magma is calculated to avoid overheating of any individual portion of the mass.

In the commercial use of minglers of the second type described above a heretofore unexplained impairment in efficiency has been endured for many years, that is, a substantially smaller percentage of crystalline sugar is found in the mass leaving the mingler than would be expected from analysis of the mass entering the mingler and from other considerations familiar to those working in this art.

I have found that the comparatively low yield obtaining when minglers of the second type are employed is due to local overheating of the magma and a consequent tendency for the sugar crystals to re-dissolve, and that the local overheating occurs even though the mass of magma-is Within the permissible temperature range and the relation of the temperature of the coil portions to their velocities through the mass is such as practically to insure no local overheating on that score. More particularly, I have found that the impairment of efliciency is .due largely to local overheating of the magma during those constantly recurring-abnormal periods when the level of the magma in the mingler is low enough to expose the rotating coils. When portions of the rotating coils break through the surface of the magma I have observed that they carry some of the magma with them, and it appears that the time the magma thus adheres to the hot coil portions before it re-enter's the mass and is swept off is long enough to overheat the magma and to cause substantial loss due to re-dissolution of the sugar crystals.

Those familiar with the operation of sugar refineries are fully cognizant of the fact that the so-called abnormal condition just described actually obtains a great part of the time. It is brought about in part by the fact that the supply of sugar bearing material to the refinery is highly variable, depending as it does on agricultural, market, and shipping conditions and other factors over which the refner has no control, so that of the huge banks of minglers many are put into or out of operation during the day. Furthermore, there are many interruptions in the reiinery processes which produce a' highly variable rate of flow of magma to the minglers and sustained periods kof operation of at least some of to produce an the minglers at substantially less than normal ocapacity, In briei, the operating conditions steam passes.

are such that the total mingler-hours during which the magma level is unavoidably so low as to expose the coils is great enough that the loss of yield due to overheating as described by applicant is quite substantial.

The long unexplained impairment in eii'iciency as hereinbefore described having been traced to its source by applicant, it is proposed in accordance with the present invention to remedy the difiiculty by providing means for reducing the temperature of the coils of the hot mingler during those intervals when the magma level is so low that the coils break through the surface. The reduction in the temperature of the coils is preferably effected by means automatically responsive whenever the level of the magma drops to the point where the sugar bearing material adhering to the coils in their rotation when they rise above the surface thereof is in danger of caramelization or substantial injury, and so operating that the supply of heat to the coils is stopped or materially retarded. Consequently, if the materialfalls below this point, the iiuid medium in the coils is suillcient to maintain the material within the predetermined range since the volume of material in the tank is markedly reduced and no danger of overheating or harmfully injuring the sugar bearing material is present. In the practise of this invention, therefore, three desired results are attained: the material is maintained within the optimum range; no caramelization or destruction occurs; and heat energy is conserved.

Amore comprehensive understanding'of means for carrying this invention into practice is obtained by'reference to the accompanying drawings in which:

Fig. 1 is a front elevation partly in section oi' apparatus employed for the temperature conditioning of sugar bearing material in accordance with this invention;

Fig. 2 shows a modification of a portion of the apparatus represented in Fig. 1;

Fig. 3 illustrates a di'erent system of producing the temperature conditioning of the sugar bearing material from that shown in Fig. 1; and

Fig. 4 shows an embodiment for controlling the temperature conditioning apparatus.

In Fig. 1, a tank I is normally i'llled with water II or other iiuid medium. The water is heated by a plurality of coils I2 through which valve |3 controlled by a thermostat I4. From the tank I0, the hot Water passes through a pipe I5, through apump I6, to a pipe |1. From the pipe l1, the hot water is transmitted through a valve I8 to a pipe I9 and thence through a plurality of rotating stirring coils 20 located in a tank 2| in which magma or other sugar bearing material 22 is contained.

The rotating stirring coils may be constructed in accordance with the system described in the copending application of applicant, Serial No. 160,178, iiled on August 20, 1937. The rotating stirring coils are xedly attached to a hollow shaft 23 supported by twobearings24 and 25. A baille or wall 26 serves to direct the flow of hot water from the pipe I9 to the outer coils initially as noted in the above stated application of applicant.

'I'he steam is admitted through a lAfter the hot water ilows through the rotating coils 23, it passes from the hollow shaft 23 through a conduit or pipe 23 to the tank III. The system for effecting a limited temperature change in sugar bearing materials shown and described in the copending application of applicant, Serial No. 236,659, iiled October 24, 1938 may also be advantageously employed in the system shown in Fig. l. f

'I'he magma or sugarbearing material 22 is supplied to the tank 2| for temperature conditioning through a conduit or pipe 30, and the control of this supply is regulated by means of a valve 3|. 'I'he magma is withdrawn after the conditioning through either of two valves 32 and 33 connected respectively to pipes 34 and 36 for processing in centrifugal machines (not shown).

' During the processing of sugar bearing materials to obtain sugar therefrom, the magma, massecuite, or other sugar bearing material 22 is withdrawn from the tank 2| and replenished at intervals from the source of supply of the material through the pipe 30 and valve 3|. As a result of this practice, the level of the magma in the tank 2| changes. Frequently the level is a substantial distance below the highest horizontal position which the stirring coils 20 attain in their rotation. When this condition prevails, the magma adheres to the hot coils when, in their rotation, they rise above the surface of the magma. Caramelization or other destruction of the sugar occurs. The possible dangerto the magma is aggravated by the consequentially higher temperature of the hot Water in the coils due to the smaller volume of magma to be heated. To prevent the destruction of the sugar, the valve I8 controls the volume of hot iluid medium entering the coils 20 in accordance with the height or volume of the magma in the tank 2|. This control is effected in the embodiment shown in Fig. 1 by a ball iioat 36 adapted to iioat on the surface of the magma 22 in the tank 2|. Fixediy attached to ball iloat 36 is a rod 31 joined at one end of a lever 38 to pivot at a pintle 38. 'I'he other end of the lever 38 is attached to a rod 46 by means of a pintle 4I. The lever 38 turns about a pintle 42 supported by a bracket 43 iixedly attached to tank 2| by means of a bolt 44. 'I'he rod 40 is connected by means of a pintle 45 to one end of a rod 46, the other end of which is flxedly attached to a valve head 41 of the valve I8. When the valve head 41 is lowered out of engagement with an associated valve seat 48, water ilows from the pipe I1 to the pipe I9 and thence through the rotating coils 20. When the valve head 41 is raised to close the valve head against the valve seat 48, the ilow of hot water from the source I0 to the rotating coll stops. 'Ille valve is controlled in accordance with the relative height of the oat ball 36 by means of the rod 31, lever 42, and rods 40 and 46. When the oat ball is above a predetermined height, the valve I8 is completely open; i. e. the position of the valve head 41 is such that any further lowering does not change the rate of ow of water through The shaft 23 is rotated by a worm wheel 21 and a worm gear 28 driven by some suitable source of power (not shown).

the valve I8. When, however, the height of the magma is decreased below that predetermined distance, the iloat ball 36 is lowered in the tank, the valve head 41 is raised to engage its associated valve seat 48 and the iiow of hot water through the valve I8 is gradually decreased until it is substantially stopped when the valve head engages the valve seat. 'I'he valve head 41 and y ausser about a pintle 88 held by means of a bracketl 8|` valve seat I8 may be constructed so that the change in the flow through the coil may be gradual or sudden as desired for a particular range in height or volume of the magma in the tank. For example, to obtain a gradual change in the flow of the, water over a range in height of the magma. the-valve head and valve seat are deep and tapered from a very narrow cross section at the top to a large cross section at the bottom. As a.

result, the area through which the waterpasses is gradually decreased within the critical range in height for which the apparatus is adjusted. n the other hand, if a sudden stoppage of the flow of water is desired when the height of magma in the tank decreases below a predetermined minimum, the valve head and valve seat are relatively thin, and the cross sectional dimensions of the top and bottom of the valve head are more nearly the same, so that when the top of lthe head of the valve is in a plane with the bottom of the seat, the valve head engages the seat in a relatively short distance corresponding to a' small change in the height of the magma. With this latter construction, the valve head does not interfere with the flow of water through the valve I8 until the height of the magma almost approximates that at which the valve is completely closed'.

The pintle t2 is located on the lever 38 so that when the surface of the magma falls below that at which caramelization or destruction of the sugar occurs, the flow of water through the coils 20 is stopped or materially retarded, either gradually or relatively suddenly, `depending upon the construction of the valve. Preferably, this height is substantially the highest level to which the outside coil attains in its rotation about the shaft 23. The dotted configuration of the iloat ball 88', rod 31', lever 38', rod 40', and valve head4 41' represent the positions of .float ball 36, rodl 31, lever 38, rod Ml, and valve head 41 respectively, when the volume oi the magma islowered to a level corresponding to the approximate highest horizontal height that the rotatingcoils 20 attain in their rotation about the shaft 23. It is observed that in this position the valve head d1' is engaged against the valve seat 48 to stop the flow of hot water supplied to the stirring coils 20. Accordingly, when the level of the magma is considerably above the highest horizontal height that the rotating coils 2B attain, hot water flows through the coils 28 whereas, when the level falls below this height, the ow of water through the coils is stopped. As a result, no danger of destruction of sugar due to the adhering of the magma to the coils when the coils pass above the level of the magma is produced.

In Fig. 2, the flow of hot water through the stirring coils is regulated by controlling the pump which normally circulates the hot water through the stirring coils. A tank 5i) contains magma, massecuite, or other sugar Stirring coils 52 rotate in a manner similar to the coils 2li shown in Fig. 1. Hot water ilows from a pipe 53 supplied from a source (not shown) through a pump 54. 'l'he pump 5 circulates the hot water or other iiuid medium, and the circulating system may be similar to that shown in Fig. 1. A iloat ball 61 adapted to float on the surface of the magma 5I is xedly attached to a rod 55 which is pivoted to a lever 56 by means of a pintle 58. The lever 56 is connected to a rod 51 by means of a pintle 59. The lever 58 turns bearing material 5 i port 82 serves to 'contact 84 are connected which is iixedly attached to the tank 50. A supguide the rod 81 in a vertical position. One end of the rod 81 forms a right angle to control by the vertical movement thereof a switch arm B3. Normally, the switch arm 68 engages a contact 84.

Connected in series with one of thepair of leads 88 is a source of current 88.. The pair of leads 85 terminate at the pole's of a motor (not shown) which drives the pump 5B. The horizontal portion of rod 51 is so disposed in relation to the switch arm 88 that when the height-oi the magma falls below a predetermined level, the horizontal portion of the rod 51 disengages the switch arm 83 from its associated contact 84 to stop the pump M from circulating water through the system. The dotted'conflguration oi the iioat ball 81', rod 55', lever 58', rod 51', and switch arms Y 8l" indicates the position of oat ball 61, rod i8,

lever 58, rod 51, and switch arrn 68 respectively, when the height of the magma is below the predetermined level. Accordingly, when the level of the magma 8| falls below the predetermined level, the switch arm 88 is disengaged from its associated contact 88 to stop the pump 54. As a result, the circulation of hot water through the rotating coils is materially retarded.

In Fig. 3 a system is shown for the control of the ow of the hot water through the rotating coils prior to processing in centrifugal machines, in accordance with the pressure in the bottom of the tank in which the sugar bearing material is contained. A tankl `contains the magma 1i. stirring coils 12 through which iluid medium flows after passage through a pipe 13 rotate in the manner of the coils 20 shown in Fig. 1. Located near the-bottom of the tank Iii is a pressure diaphragm 14 encased in a housing 15. The diaphragm is in contact with the magma in the tank. Immediately adjacent to the diaphragm 'I4 is .a iiexing member 16 also encased in the housing 15. A right angle rod 11 is xedly attached to the flexing member 16 and passes through the housing 15. The vertical portion of the rod 11 controls a switch arm 18 to engage or disengage a contact 19. The engagement of the switch arm 18 with the contact 1S serves to provide a source of current through a pair oi leads 8i? from a source of current 8i to control any part of the apparatus. For example, the leads S8 may be connected to the terminals of the motor of a pump such as the pump 54 in Fig. 2 to stop substantially or retard materially the circulation of hot water through the coils. In order to demonstrate this control and illustrate the substitution of the portion of the apparatus shown in Fig. 3 for a portion of that appearing in Fig. 2, the broken vertical line 2--2 in Fig. 2 represents vthe division of the system into two parts, the

right hand portion of which may be replaced by the apparatus shown in Fig. 3. The dotted 3 is situated at the point at which the apparatus shown therein is substituted for the portion of the system illustrated in Fig. 2 to the right of the vertical line 2 2. In the substitution, the leads of Fig. 3 are con- .'nected to the leads es connected to the pump sa shown in Fig. 2.

The diaphragm 14 and exing member 1B are adjusted so that the rod 11 disengages the switch arm 18 from the contact 19 when the pressure of The switch arm 88 and," to a pair of leads 88.

-magma adheres to the coils 12 when these coils pass in their rotation above the surface of the magma to afl'ect the sugar detrlmentally. Usually this level is the highest horizontal position attained by the coils in their rotation. In operation, when heated magma 1| is withdrawn below the critical level, the diaphragm 14 and ilexing member 16 effect the stopping of the pump 54 from sending any substantial flow of water through the coils 12. When cold magma is added to the tank 10 to increase the height or volume in the tank above the critical level or volume, the diaphragm 14 and ilexing member 16 return to their normal positions, the switch arm 18 engages the contact 19 to connect the source 8| to the pump 54. The resulting operation of the pump 54l effects the resumption of the ow o1 hot water through the coils 12.

In Fig. 4, a diiierent means of controlling the temperature of the stirring coils in the tank when the volume decreases below a predetermined amount is shown. A tank 85 which supplies the heated iluid medium, such as hot water, to the stirring coils is heated by means of steam circulated through coils 89 contained in the tank, similar to the coils I2 in the tank l0 shown in Fig. 1. 'I'he steam is supplied to the coils 89 through a valve 86. The valve comprises a valve head 81 which engages a valve seat 88 to stop the i'low of steam to the coils 89. The valve head 81 is biased to engage the seat 88 by a helical spring 9|) which encircles a piston 9| xedly attached to the valve head 81. The valve head 81 is held out of engagement with the seat 88 by the energizing of a solenoid 92, through the center of which the piston 9| passes.

The heated fluid medium from the tank 85 passes through a pipe 93 and a pump 94 to a conduit or pipe 95, to supply stirring coils located in a tank containing magma or `other sugar bearing material in accordance with a system similar to that shown in Fig. 1. A pair of leads 96 furnishes a path for energizing the solenoid 92. 'Ihe dotted vertical line 4-4 represents the place at which portions of the apparatus shown in Figs- 2 and 3 to the right of .the dotted vertical lines 2 2 and 3-3 respectively are employed with that shown in Fig. 4. In the event that the actuating apparatus is that shown to the right of the dotted line 2--2 in Fig. 2, the leads 96 are connected to the leads 65 to supply normally current to the solenoid valve 92 from the source 66. Accordingly, when the volume of magma in the tank 50 is above the critical amount, the oat ball 61 is positioned so that the switch arm 63 engages the contact 64. Solenoid 92, under these conditions, is energized, the valve head 81 is disengaged from the valve seat 88, and steam ows through the coils 89. When the volume of the magma decreases below the critical amount, however, the float ball 61 falls to disengage the switch arm 83 from its associated contact 64. The

.source 66 is, as a result, withdrawn to deenergize solenoid 92. 'I'he spring 98 eilects the enseat 88 to stop the flow of steam through the coils 89. Since the fluid medium in the tank 85 is no longer supplied with heat from the coils 89, its temperature drops. The uid medium flowing through the stirring coils 52 is markedly cooler than that usually supplied- The magma adhering to the coils is not heated to a harmfully high temperature. When cold magma is poured into a tank 50 to increase the volume above the predetermined amount, the switch arm 68 engages the contact 64 to energize solenoid 92. The valve head 81 Ais disengaged from the valve seat 88 to permit the passage of steam to the coils 89.

In the event that the actuating apparatus is ythat shown to the right of the dotted line 3-3 shown in Fig. 3, the leads are connected to the leads 96, to supply current from the source 8| to energize solenoid 92 as long as switch arm 18 engages contact 19. If the height of the magma falls below the predetermined value, the diaphragm actuates the disengagement of the switch arm 18 from contact 19. Solenoid 92 is deenergized to stop the passage of steam to the coils 89. As heretofore described, the action cools the stirring coils such as the coils 12 so that the sugar bearing material adhering to the coils is not harmfully ailected. When the magma is replenished to increase the height above the predetermined value, the diaphragm returns to its former position. The switch arm 18 engages the contact 19 to energize solenoid 92. 'Ihe energizing of solenoid 92 results in the passage through the valve 86 of steam to the coils 89.

'Ihe control ofthe supply of the uid medium to the rotating coils may be accomplished in a manner other than that specifically described in detail. For example, the valve I8 shown in Fig. 1 mechanically operated by the float ball 36 may regulate the amount of steam supplied to the coils in a way similar to the control effected by the valve 86 of Fig. 4. Again, the pressure switch comprising the diaphragm 14, flexing member 16, rod 11, switch arm 18 and contact 19 of Fig. 3 can operate a solenoid Yvalve similar to the valvev 86 controlled by solenoid 92 of Fig. 4 located in the path of the supply of the hot water to the stirring coils. 'I'he location of the valve may be just anterior to the entrance of the hot water into the stirring coils, positioned, for example, as shown by the valve I8 of Fig. 1. Instead of utilizing the pressure switch of Fig. 3 to operate the solenoid of this valve, the float switch of Fig. 2 comprising oat ball 61, rod 55, lever 56, rod 51, switch arm 63 and contact 64 may be employed for this purpose. Then, too, several means of `controlling the temperature of the stirring coils may be employed simultaneously. To illustrate, the passage of uid medium to the stirring coils may be stopped as shown in Fig. 1 and the steam prevented from entering the coils in the tank as shown in Fig. 4. Further, other instrumedium could be heated by an electric current.

and the source removed in a manner similar to that described, when the height of themagma in the tank passes through a predetermined level;

While preferred embodiments of this invention have been illustrated and described, various modications may be made therein without departing from the scope of the appended claims.

What is claimed is:

1. A hot mingler for the temperature conditioning of sugar magma or the like comprising a tank for containing the magma, a heating surface within said tank normally covered by said magma, heat supply means normally maintaining said heating surface at a temperature substantially in excess of the highest temperature to which said magma could be heated without deleteriously affecting it, means for establishing relative movement between said heating surface and said magma wherebyheat from said heating surface is distributed throughout said magma, the said relative movement being such that said heating surface breaks through the surface of said magma when the level thereof is lower 20 than normal, and means controlled by the level of said magma and operating on said heat supmass of magma is substantially reduced.

2. A combination in accordance with claim 1 in which said heat supply means transmits hot fluid to said heating surface and in which said controlled means controls the rate of iiow of said fluid to said heating surface.

3. A combination in accordance with claim 1 in which said heat supply means transmits hot fluid to said heating surface and in which said controlled means operates to reduce the temperature of said fluid as delivered to said heating surface.

CHARLES A. OLCOTT. 

